1. Field of the Invention
The present invention relates to the field of speaker rigging systems and more particularly to a system to be used for large venue touring.
2. Description of the Prior Art
A large venue touring sound system comprises a number of high output loudspeakers and a method of rigging the speakers into suspended vertical columns known as "sound columns" or vertical arrays. In a typical venue, multiple arrays of speakers are required to achieve adequate sound coverage, intensity, and quality.
Large venue touring sound systems are typically used by "rock and roll" bands on nationwide and worldwide tours. On a typical nationwide tour a band will play in twenty or thirty cities. The number of nights a concert is performed varies and may be as few as one night in smaller cities and is typically fewer than five nights even in large cities. Venues where concerts take place also vary from large outdoor stadiums capable of holding 80,000 or more people to smaller indoor arenas which may seat as few as 15,000 people.
Thus, a touring sound system must be capable of being quickly assembled and suspended in vertical arrays prior to a performance. Of equal importance is the ability to quickly disassemble the sound system, load it onto trucks, and transport it to the next venue subsequent to the performance. In addition, a touring sound system must possess a high degree of flexibility as the requirements in terms of the number of arrays required and the complexity of the rigging hardware may vary considerably between an outdoor stadium and a comparatively smaller indoor arena.
From a practical standpoint, factors that must be considered in setting up a sound stage include the number of speakers required; the corresponding complexity of the suspension apparatus; the number of man-hours required to set up and tear down the system; as well as the truck space required to transport the system. Safety is also a significant concern as high capacity loudspeakers are of substantial weight and the complexity of the rigging system creates significant potential for accidents.
Acoustical factors are also important to the success of a large venue touring sound system. Acoustics engineers have learned that superior music reproduction occurs when a series of speakers are arranged in a spaced vertical relationship to form a "sound column" or vertical array. Experience has shown that vertical arrays increase sound intensity in the horizontal plane of an audience and lose substantially less sound intensity through vertical dispersion than other speaker arrangements. Recent research has shown that the performance of vertical arrays can be further improved by carefully controlling gap size and minimizing gaps between high frequency elements. Ultimately, the success of a large venue touring sound system depends to a large extent on its ability to adequately address each of the practical and acoustical concerns in a cost effective manner.
The traditional approach to rigging a sound system for a large venue involves the construction of an elaborate multilevel space frame. In large stadiums such frames are often two or three stories high and in excess of 100 feet in width. Vertical arrays are constructed by suspending speakers in long columns from the frame. The suspension apparatus typically consists of chains or cables to which the speakers are attached. Various means of connecting the speakers to the chains or cables are in widespread use. These include belt and buckle type fittings, clevis and shackle arrangements, as well as claw type devices where a claw interfaces with a fixed stud, ring, or hook mounted on the speaker case. The prior art methods have long been plagued by numerous drawbacks. Vertical arrays suspended from either chains or cables are flexible and tend to sway in even a light breeze. Thus, the speakers must be spaced sufficiently apart horizontally to account for this motion. In addition, the space frame supporting the vertical array must be designed to provide stability to the swaying columns and is therefore more elaborate and heavier than would otherwise be required. Further, the means of attaching the speakers to the chains or cables, whether of the belt and buckle type, clevis and shackle type, or of the claw type, are inherently slow and therefore substantial man-hours are required to assemble and suspend multiple arrays. The prior art methods typically require the installer to use both hands to couple the speaker to the chain or cable which can be a serious safety concern given the weight of the speakers and the height at which they are commonly suspended. The prior art methods also require the transport of large quantities of bulky hardware in addition to the speakers themselves. Such hardware consumes substantial truck space and is relatively heavy and therefore incurs significant transportation costs. Finally, none of the prior art methods are able to maintain the close vertical spacing between speaker cabinets that recent acoustics research indicates is desirable to increase the efficiency of a vertical array.
An example of the chain style of suspension is U.S. Pat. No. 4,660,728, entitled "Flying Sound Systems", issued to Martin, Apr. 28, 1987. Martin discloses a method of attaching speakers to a pair of suspended chains. Martin places a coupling device on the sides of the speaker cabinets that interfaces with a mating device which can be attached to hanging chains. The back panels of the speakers are connected by straps in an effort to provide some degree of stability to the chain suspended speaker array. Although the coupling device taught in Martin demonstrates creativity in design, it is complex and not demonstrably faster than a conventional shackle and ring arrangement. Further, the straps Martin places on the backs of the speaker cabinets are themselves flexible and thus do not significantly increase the rigidity of the speaker column. Nor can the system disclosed in Martin maintain close vertical spacing between speaker cabinets.
An example of a space frame approach is shown in U.S. Pat. No. 5,602,366, entitled "Space Frame With Array Element Positioning" issued to Whelan et al, Feb. 11, 1997. This patent discloses a variation of the traditional space frame used to stack a vertical column of speakers. Although effective, the patent demonstrates the complexity of connections and the bulk of structure associated with even a relatively small space frame.
What is needed therefore is a modular rigging system expressly designed for the creation of "sound columns" for use in large venues. Ideally, the system should be able to create a rigid vertical "sound column" and should possess the capability to quickly couple and just as quickly uncouple the vertical array of speakers. Further, the system should require a minimum of hardware. Ideally the means for vertical suspension would be contained within the speaker cabinet itself, thereby eliminating the need for chains or cables and their associated rigging hardware. In addition, the mechanism used to couple the individual loudspeakers should be designed to provide for a minimal gap between each loudspeaker in the vertical array.